In order to experience outer space first hand, space suits are needed to protect astronauts from the extreme environment. The human body requires pressure to be continually and evenly applied. On Earth, the atmosphere applies 101.325 kPa (I atmosphere at sea-level) to the surface of the human body. In the vacuum of space, pressure must be applied using a pressurized capsule or space suit. The safe minimum pressure is limited by breathing pure oxygen at a pressure of 25.33 kPa, although this low pressure requires a long duration of time to transition from an atmosphere with inert gases to avoid decompression sickness. Ideal space suits would have a pressure of 101.325 kPa to have zero transition time, but this makes traditional space suits too stiff to move.
Current space suits limit astronaut mobility and cause fatigue. Arthur Iberall worked on ways to develop mobile pressurized space suits and developed the concept of the Lines of Non-extension (LoNEs) to describe the deformation and motion of human skin. LoNEs are contours along the human body where the skin does not stretch. Other approaches to make mobile space suits were developed, such as the Space Activity Suit, a mechanical counter pressure (MCP) space suit that used material elasticity to pressurize the body instead of gas pressure. In 2001, the concept of a fully MCP spacesuit reemerged at the Massachusetts Institute of Technology (MIT) as the Bio-Suit. The concepts of MCP have also been applied to different components of space suits, such as gloves.
Research on skin deformation and physiology dates back to the mid-1800s with Karl Langer's 1861 study of the direction in which the skin deforms when punctured. The directions and lines are now known as Langer Lines. Space suit and bio-medical research has progressed our understanding of skin's deformation characteristics. This body of research has developed various techniques to quantify skin strain using laser scanning and motion capture systems. However, in past research, measurements have been limited to 1 cm2, which limits the ability to accurately compute LoNEs. Using past techniques, it was also difficult to analyze multiple subjects. Thus, there is need for new measurement techniques that improve upon prior techniques.